The ultimate goal of this research is the development of sensory aids which sample the acoustic environment at more than one point in space (multimicrophone aids) to improve the ability of hearing-impaired subjects to function more effectively in complex environments containing interference and reverberation. The more immediate goal is to explore the potential of multimicrophone systems for monaural listening in such environments. The results of this research, combined with research on binaural interaction in impaired listeners, will provide solid background for the development of multimicrophone aids to assist impaired listeners who have significant hearing in either one or two ears. The proposed research, which draws heavily from previous work on both natural and artificial spatially diversified sensor systems (binaural hearing and antenna/signal-processing theory), is concerned primarily with reduction of interference and coding of spatially resolved information. The techniques considered for reducing interference include both linear and nonlinear processing, and both fixed and adaptive processing. The study of spatial coding, which is motivated by the need to monitor the general acoustic enviornment as well as to focus upon a particular source, is concerned with the extent to which signals that are spatially resolved physically can be processed for monaural listening so that the resolution is preserved at the perceptual level. Results on the reduction of interference should be applicable to cochlear-implant aids and sensory substitution aids as well as conventional acoustic aids.